Multi-circuit electrical connectors of the type adapted for mounting on a printed circuit board typically include a plurality of electrical contact members or terminals disposed within a unitary dielectric housing, normally a molded plastic housing in which the terminals are inserted following molding. In these assemblies, the housing typically surrounds portions of the terminals adjacent the printed circuit board to provide rigid support for the terminals. In some instances, one or more mounting posts are molded integrally with the housing and are positionable in holes in the printed circuit board.
The terminals of such connector assemblies often have solder tails insertable through holes in the printed circuit board for soldering to circuit traces on the board and/or in the holes. The solder tails sometimes are used to lock the connector assembly to the circuit board prior to soldering or at least to maintain the connector assembly mounted on the board during soldering of the assembly to the board. This locking often is accomplished by enlarged head portions or laterally projecting hooks which snap under the bottom side of the printed circuit board and thereby hold the connector assembly to the board. The terminals may be thin stamped contact members, with a stamped locking hook projecting outwardly from one side of the solder tail portion for locking under the bottom side of the board.
One of the problems in using "hooked" solder tails of the terminals for locking the connector assembly to the circuit board is in accommodating variances in the size or location of the holes in the board through which the solder tails are inserted and variances in the dimensions of the solder tail. U.S. Pat. No. 5,076,804 to Bertho et al, dated Dec. 31, 1991 and assigned to the assignee of this invention, is directed specifically to those problems in "hooked" solder tails by providing an electrical connector assembly with terminals which have hooked solder tails considerably less sensitive to variations in the holes in the printed circuit board.
Another approach involving the use of the solder tails for maintaining an electrical connector assembly mounted on a printed circuit board during soldering of the assembly to the board is shown in U.S. Pat. No. 4,847,588 to Doutrich, dated Jul. 11, 1989. Rather than employing stamped terminals, the electrical connector assembly disclosed in that patent uses a plurality of terminal pins which are relatively thick and stiff. Ends of the pins define the solder tails. A few of the total number of pins in the connector assembly have offset portions in the form of crimps. Each crimp is shaped so that each pin contacts the printed circuit board only within its respective hole and only on one side of the hole and only at its crimp. This patent specifically discloses that the crimp exerts a relatively high normal force against the board at one side of the respective hole, and the remainder of the pins are straight (i.e. without a crimp).
One of the problems in using thick and stiff pins as the solder tails in connector assemblies as described above, again revolves around accommodating variances in the size or location of the holes in the printed circuit board into which the pins are inserted and variances in the dimensions of the solder tails. Forming thick and stiff pins with crimps, as described above, is not near as exacting a fabrication technique as in stamping metal. Therefore, the crimps must be offset an excess amount to accommodate the variance of tolerances in the solder tails to ensure they contact the circuit board holes. In many assemblies, this results in unduly high insertion forces in mounting the connector assembly to the board. That is why only a few of the solder tails of the stiff and thick terminal pins in the U.S. Pat. No. 4,847,588 are crimped, while the remainder of the pins are straight. Therefore, two different types of terminal pins must be fabricated for use in a single connector assembly which, of course, increases the costs of manufacturing the assembly.
It can be seen from the above that, whether connector assemblies employ stamped "hooked" terminals or thick and stiff crimped terminals, problems continue to persist in using the solder tails of the terminals as the means for maintaining an electrical connector assembly mounted on a printed circuit board during soldering processes. The present invention is directed to an improved electrical connector assembly of the type adapted for mounting to a printed circuit board, utilizing the solder tails of the terminals for holding the assembly to the board during soldering.